Hormones

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-endocrine glands and other organs with hormone secreting cells-hormones are chemical signals-hormones effects can occur in seconds or hours and may lawt a few minutes or several days

Visualize the human endocrine system

3 classes of hormones

1) Amines: derived from tyrosine or tryptophan2) Proteins/peptides: most hormones3) steroids: cholestoral derivatives, less soluble in water - use carriers

Describe amine and protein/peptide hormones

-water soluble-not able to cross plasma membrane-must use receptor on the cell surface

Describe hormones are lipid soluble

-diffuse across plasma membranes and acces receptors in either the cytosol or nucleus

Hormone receptors

-only cells having the proper receptors can respond to a hormone-hormones activate only specific cells-hormone interacts noncocalently and reversibly with the receptor - prevents cells from being permanently stimulated

Water soluble hormone receptors

-receptors on the plasma membrane - amine and protein/peptide hormones (except thyroid hormone)-binding initiates a cascade culminating in intracellular signalling-signaling pathways: rapid, occuring in seconds, involve activity of enzymes, a signle signalling molecule results in the production of many intracellualr messages

Lipid hormone receptors

-receptors located within the cell (in the cytosol or nucleaus)-steroid hormone-receptor complex acts as transcriptional activator to enhance particualr genes-transcription of gene enhance and more of that gene's product produced-can influence a number of fenes within a single cell or in different cells

1) sensory stimuli detected by the nervous system can activate the endocrine system-sensory cue preceived by a sensory receptor sends electrical stimuli to different brain areas including the hypothalamus-hypothalamus and pituitary gland play the major roles in linking the nervous and endocrine systems

Hypothalamus and pituitary gland

hypothalamaus is a collection of seceral nuclei at the base of the brain and can talk to anterior and posterior pituitary gland

-hypothalamic nuclei make neurohormones: any hormone made and secreted by neurons but NOT neurotransmitters-neurons secrete neurohormones into capillaries-travel through portal vein to anterior pituitary-anterior pituitary then synthesizes several different hormones: 6 hormones swcreted in to general blood circulation, act on other glands or structures

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Posterior pituitary gland

-blood supply not connected to hypothalamus-does not respond to hypothalamic neurohormones-neurons in the hypothalamus synthesize 2 hormones that have axons that terminate in the posterior pituitary and release the hormones

-stimulates energy consumption-also increase heat production-iodine stored in case of deficiency -iodine deficient goiters can result from low iodine in the diet

Pancreas

-exocrine portion releases contents into small intestine for digestion-endocrine portion - islets of langerhans-5 cell types: greek elterrers-two are important for glucose homeostatis (alpha and beta)-alpha cells make glucogen and raises blood glucose-beta cells make insuline and lowers blood glucose

Adrenal glands

-when blood glucose levels are lower than normal: neurons from the sympathetic nervous system activate the secretion of epinephrine by adrenal medulla (stimulates glycogenolysis and gluconeogenesis)-produce glucocorticoids like cortisol (which activates gluconeogenesis in the liver)

Type 1 diabetes mellitus (T1DM) and Type 2 Diabetes mellitus (T2DM)

Type 1-immune system has mistakenly destroyed beta cells-glucose acculuates to high level in blood-treated by administration of insulinType 2-cells of the body lose much of their ability to respond to insulin-obesity associated

Isolating insulin

-had been unable to pruify glucose lowering factor due to digestive enzyme inference-1921: ligate pancreatic ducts to destroy exocrine pancreas and then purify the factor from the remianing pancreatic tissues-first successful test on humna patients of purified insulin in 1922

Rest of isolating insulin

Leptin

regulates appetite-released by adipose cell in proportion to amount of adipose tissue in the body-acts on hypothalamus to inhibt appetite-decreasing adipose tissue decreases leptin incresing appetite

-tightly regulated-no large reservoirs like Calacium in bone-key is altering rate of reabsorption of water, Na+, K+ from urine-ADH increases reabsorption of water in kidney-atrial natriuretic peptide (ANP): secreted from atria of heart to decrease sodium reabsorption in kidney-Aldosterone from adrenal glands increases sodium reabsorption in kidney